Hi Alec,
Actually, scratch that -- after upgrade, the article_notes table is completely empty, and the note appears as it should in the notes table as it should. If I go directly to the Edit interface and edit the note, my edit is reflected in the notes table, and the note actually then appears in the Submission Notes listing.

(In reply to comment #3)
> James, does this mean that after the upgrade the notes are somehow in a bad
> state, but that editing them and saving them corrects that state? Or do I
> misunderstand?
It looks like the context_id field isn't being set properly on upgrade. All note context_ids are set to null after the upgrade is complete, but switch to 1 when I edit and save a note. Notes only display when the context_id is set to 1. The attached table xml dumps should be fairly self-explanatory; you'll see that in notes_post-edit.xml only one context_id field is 1 -- that's because I only edited the one note.

(In reply to comment #9)
> James, could you try the attached patch? You may need to patch bug #6220 first,
> before this patch will apply cleanly. It'll need to be applied before you run
> the upgrade process.
Hi Alec, that appears to do the trick. I'm guessing that if the upgrade process has already been completed, users running into this issue can just set the context_id fields in the notes table to 1?

(In reply to comment #12)
> (In reply to comment #9)
> > James, could you try the attached patch? You may need to patch bug #6220 first,
> > before this patch will apply cleanly. It'll need to be applied before you run
> > the upgrade process.
>
> Hi Alec, that appears to do the trick. I'm guessing that if the upgrade process
> has already been completed, users running into this issue can just set the
> context_id fields in the notes table to 1?
Oops -- just looked at the patch -- that would be, they set the context_id to the relevant journal ID.

In upgrade from 2.2.3:
[data: dbscripts/xml/upgrade/2.3.3_update.xml]
ERROR: Upgrade failed: DB: Unknown column 'notes.context_id' in 'field list'
The notes.xml schema doesn't seem to have a context_id, which I assume should? Also, there still appears to be an article_notes definition in ojs_schema.xml. And to be a real nitpick, the table comment in notes.xml refers to the groups table.